Draw-bridge



(No Model.)

M. A. ZURGHER.

DRAW BRIDGE.

No. 255,831. Patented Aprll, 1882.

\/\/iT [55555: ViNVENTnR Wd. f4@ M h UNITED STAT-Es PATENT OFF-rca.

MAX A. ZRGHER, OF` GH1CAGO, ILLINOIS.

DRAW-empoli;`

SPECIFICATION forming part of Letters Patent No. 255,831, dated April 4, 1882.

Application inea January 14, rese. (No model.)

Figure 1 is a side elevation of a bridge con-` structed in accordance with myinvention Fig. 2, a plan view of the samepshowing the bottom chords and operating mechanism; land Fig. 3, a plan view, showing the upper bracing. 4

My invention relates to draw-bridges of the class that are opened by being turned upon their centers in a horizontal Vor nearly horizontal plane; and my primary object is to produce a discontinuous draw-bridge in which the two spans crossing the separate openings shall, when closed, be absolutely independent of each other, whereby the action of a moving load upon the bridge when closed can be exactlycalculated, which is not the casein acontinuous draw-bridge.

My invention consists broadly in combining with the center pier, swinging mechanism, and abutments the following elements, viz: first, two independent spans, one crossing each opening of the draw, each span being hinged at its inner lower end to struts or girders resting upon or attached to the turn-table upon the center pier, or otherwise adapted to work upon the turn-table as a fulcrum, `and thus be raised and lowered at its outer end without changing its elevation at and between the fulcrums; and, second, mechanism of any suitable character at the center of the bridge for raising the outer ends ot' thespans from the abutments,eitherscparately orsimultaneously, and lowering them thereon.

My invention consists, also, in the specic mechanism by means of which I carry out my invention, and also in various details of construction and combinations of parts, all as hereinafter more fully set forth.

In the drawings, A is the center pier, B the turntable, and C C the abutments.

D D are the two spans, each of which, when .the bridge is closed,rests at its innerend upon the turn-table B and at its outer end upon one of the abutments, as shown in Fig. 1. The inner ends are represented in the drawings as connected to the central sections of the bot'- tom chord, bearing on the turn-table by hinges o. They may, however, be hinged or pivoted iu any other manner that will maintain them in place. When resting upon the abutments the outer ends are secured against lateral movement by means otl the blocks u; but ot' course any other securing device from which the ends might be released by lifting, with or without the interposition of other mechanism at the ends, would be the equivalent of the blocks a. lt is obvious that the blocks vu may also be made adjustable vertically by suitable means to allow for discrepancies in level or for any other reason. The object sought is to lift the ends of the spans by mechanism acting at the center of the bridge sufficiently to permit the turning, and it is of course preferable to have the same motor which turns the bridge also1L perform the ottice of raising thc ends. One of the various ways by which all this may be effected is shown inthe drawings, and is as follows:

E isaright-and-leIt-hand screw formedupon the upper part of a spindle, F, mounted vertically in a strong standard, G, and projecting below the bottom chord, where it is provided on its lower end with a beveled-gear wheel, t. 0n the screw E are two nuts, s s', one being on the right hand portion of the screw and the other on the left, and both working in suitable guides, g, on the standard G. Both nuts are connected to the adjacent upper end of the truss or girder by pivoted rods or members i' and r'. A device similar to the one above described is formed on an-yor all trusses or girders ofthe bridge. It is also obvious that by turning the screw Ein onedirection the nutss and s' are carried away from each other, and, through the medium of the rods or members r and 1"', shorten the distance between the inner ends ot' the top chords of the bridge, thus lifting the ends ofthe spans from their abutments, all as indicated by the dotted lines in Fig. 1,- while if turned in the contrary direction the said nuts and rods are carried toward each other, and

ICO

the distance between the inner ends of the top chords will be increased, and will thus allow the outer ends of the spans to descend. In practice, when the ends of the spans are thus lowered the nuts are brought toward each other `Aother suitable agent for operating them may be substituted for the right-and-let't screw without departing from my invention.

To operate the screws by means ofthe en gine H, I provide a transverse horizontal shaft, I, revolving in bearings q upon the turn-table, and having beveledgear wheels p meshing with the beveled-gear wheels tupon the lower end ofthe screw-spindle. Another gear-wheel, o, upon this shaft meshes with a gear-wheel, u, upon an extension of the crank-shaft m, which is turned by the engine and operates the Ordinary' bridge-turning mechanism K L.

It isclear that the engine must not be permitted to act upon the turning and lifting mechanism simultaneously. I therefore provide two clutches, Z and l', of the well-known construction, the first to connect or disconnect the lifting mechanisn at will and the second to connect or disconnect the turning mechanism. Any well-known device may be employed for this purpose, and, if desired, it may be made automatic.

The engine may be located in any place or position which the particular construction of the bridge renders most expedient, and the various mechanisms adapted accordingly.

The operating mechanism may be worked by steam, hand, or any other motive power.

To preclude all possibility of torsion while swingingthebridge, the innerends of the ripper chords may, if desired, be connected to the opposite upper nuts, s, or to the opposite lower nuts, s', or to both, by means of the diagonal lateral braces 7c, each of these braces being pivoted both to the chord and the nut, whereby it conforms to the movement of the bars t* and 1^. Also, the opposite nuts are connected together by struts t and the ends of opposite chords by struts i. t

What I claim as new, and desire to secure by Letters Patent, is

1. In a draw-bridge, the combination, with the center pier, swinging mechanism, and abutments, of two spans, one crossing each opening and hinged or pivoted in place atits inner end, and mechanism at the center of the bridge for raising the outer end of each'span fromits abutment and lowering it thereon, substantially as described.

2. In combination with the center pier, abutments, and turn-table of a draw-bridge, the two spans D, each pivoted at its inner end, as described, pivoted rods or members r and v', connecting the inner ends of the upper chords of the spans and forming a double knucklejoint, asy sli'own, and mechanism for moving the linked inner ends of the rods or members v to or from each other at'will to raise or lower the outer ends of the spans, as set forth.

3. In combination with the center pier, abutments, and turn-table of a draw-bridge, the

two spans D, pvoted at their inner ends, as

described, pivoted rods or members r and r', connecting the upper chords ofthe span, nuts s ands', rightandlefthand screw E, passing through the nuts and braced in a suitable standard, and mechanism for turning the screw either way, substantially as described.

MAX A. ZURCHER. In presence of C. C. LINTHICUM, WM. H. DYanNFonrH. 

